The present invention relates to an optical sighting device for day or night sighting and more particularly to a reflex sighting device.
Reflex sights are well-known and have taken a variety of forms, such as in gun sights and camera view finders. In substantially all forms, however, some type of reticle pattern is utilized to mark the area or object of interest. Light or the illuminated image from this reticle pattern is reflected from a semi-transparent, semi-reflective mirror or lens surface through which the object or field is viewed. The curvature of the semi-reflecting surface is such as to direct the reflected rays of the reticle image to converge approximately at the same viewing point of the operator as the transmitted rays of the object or field being sighted and thereby to make the reticle pattern appear at infinity and superimposed upon the object or field and at approximately the same distance.
In accordance with the present invention there is provided a reflex sight comprising a reticle and a dichroic beam combining mirror for combining rays of light from the reticle with rays of light from an object or field. The dichroic mirror has high reflectance in one part of the visible spectrum and high transmittance in the other parts to provide the dual image to the viewer or operator.
It has been found that in using sighting devices, for example for aiming weapons, cameras and the like, that sighting with both eyes open is advantageous. When sighting with both eyes open, the operator has the benefit of binocular vision which increases the field of view, provides depth perception information, increases contrast sensitivity and assists the sense of balance. The assessment of the speed and direction of moving objects is also more accurate.
Temporarily closing one eye during aiming interrupts the visual signal from one eye and can begin to change the state of light adaptation and point in space upon which the open eye was fixed.
As noted, frequently a dichroic mirror is utilized in reflex sights. Such a dichroic mirror reflects nearly all light above one wavelength and transmits nearly all light below that wavelength. If a red or orange dot is used as the aiming mark or reticle, the mirror will reflect red/orange light and transmit yellow, green and blue light. Thus the dichroic mirror changes the color of a target scene. If the target is viewed with one eye only, the loss of the red color from the target area will be observed. When the other eye is opened, the missing color will be put back into the target scene perceived by the viewer or operator.
In general all optical sights are provided with an aiming mark or reticle and have a common benefit by presenting the aiming mark at the same focus as the target. In this regard it is believed that a reflex sight, which is non-magnifying, is particularly advantageous for aiming with both eyes open because it does not interrupt binocular vision at all, i.e. such as with telescopic or magnifying optical sights. Regardless of the type of sighting device, however, it is desirable to provide a limited contrast between the level of brightness of the reticle and that of the target or scene. However, for day and night sighting, the aiming mark contrast can be inconsistent. For example if the aiming mark or reticle is extremely bright it may be most suitable for aiming at brightly lit target scenes but could be too bright for dimly lit target scenes and, of course, the reverse is also true.
Thus aiming at a dark object in heavy shade can be difficult or inaccurate without a suitable means to improve contrast of the aiming mark or reticle. In the past, numerous ways have been devised whereby the aiming mark brightness can be varied to improve contrast with the target scene, i.e. battery powered LEDs, electric lights, etc. which are controlled manually or electronically.
In the present invention a unique construction is utilized to vary the reticle brightness in proportion to the target scene brightness in day and night sighting while providing an illumination intensity for day sighting which provides a desired contrast comparable to that of an artificial light source for night sighting. Another objective is to provide a design in which compensating variations in reticle brightness occur naturally without the need for manual adjustment such as with a brightness knob or electronic control.
A unique fiber optic structure is utilized in which a fiber optic light collector receives ambient light focused transversely or radially inwardly over a selected length of fiber whereby a desired magnitude of light energy can be gathered from ambient light to provide illumination to the reticle. In addition a radio-luminescent source is used in combination with the fiber optic collector resulting in a combined illumination whereby a desired level of illumination can be provided to the reticle over the full range of brightness during day and night sighting.
Thus it will be seen that the unique features of the present invention provide a significant improvement over other sighting devices including ones as shown and described in the U.S. Pat. No. 2,780,130 issued Feb. 5, 1957 to Mauer, U.S. Pat. No. 3,645,635 issued Feb. 29, 1972 to Steck, U.S. Pat. No. 3,905,708 issued Sep. 16, 1975 to Steck, III, U.S. Pat. No. 3,932,162 issued Jun. 13, 1976 to Blakenship, U.S. Pat. No. 3,938,875 issued Feb. 17, 1976 to Ruder, U.S. Pat. No. 4,030,203 issued Jun. 21, 1977 to Ackerman Jr., U.S. Pat. No. 4,576,451 issued Mar. 18, 1986 to Tomenaga, U.S. Pat. No. 4,665,622 issued May 19, 1987 to Idan, U.S. Pat. No. 4,764,011 issued Aug. 16, 1988 to Goldstein, U.S. Pat. No. 4,806,007 issued Feb. 21, 1989 to Bindon and U.S. Pat. No. 4,877,324 issued to Hauri et al.
Thus it is an object of the present invention to provide a unique reflex sighting device for day and night sighting.
It is another object of the present invention to provide a unique reflex sighting device with improved illumination for the reticle.
It is still another object of the present invention to provide a unique reflex sighting device in which the illumination of the reticle is varied naturally in accordance with the illumination of the target or viewing area.
It is a general object of the present invention to provide a unique reflex sighting device for day and night sighting.
It is another object of the present invention to provide a unique reflex sighting device for day and night sighting and for sighting with both eyes opened.